Theory and Design of Higher Order Sound Field Recording

This thesis investigates the theory and design of recording the spherical harmonic components of an arbitrary three-dimensional sound field. The approach taken is based on capturing the spherical harmonic components using a spherical microphone. This choice led to the investigation of various design issues including the inherent limitations of the spherical microphone, discretization of the theoretical continuous spherical microphone into a microphone array and associated spatial aliasing problems, calibration errors of these microphones and signal processing issues. A fourth order microphone design was presented and analysed, which allowed the verification, integration and evaluation of the design issues mentioned earlier, in the context of this design. Overall, the design was capable of recording a frequency range of [340, 3400]Hz, thus finding applications in future teleconferencing systems. The design can also be directly applied to beamforming applications.